Django REST framework 学习纪要 Tutorial 2 Requests and Responses

Request 对象

REST 框架引入了Request对象,继承于HttpRequest,相比HttpRequest提供了更多请求解析,最核心的功能是request.data属性,类似于request.POST,以下是不同之处。
* request.POST
1. 只能处理form表单数据;
2. 只能处理POST请求。
* request.data
1. 能够处理任意一种数据;
2. 能够处理POST、PUT、PATCH请求

Response对象

REST框架也引入了Response对象,它是一个TemplateResponse类型,能够将未处理的文本转换为合适的类型返回给客户端

return Response(data)

状态码

REST框架提供了更可读的状态信息,比如HTTP_400_BAD_REQUEST

API views封装

  • 对于函数views,可以使用@api_view装饰器
  • 对于类views,可以继承于APIView

views应用

  • 修改snippets/views.py
  1. GET获取所有code snippets,与新建code snippet的接口
from rest_framework import status
from rest_framework.decorators import api_view
from rest_framework.response import Response
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


@api_view(['GET', 'POST'])
def snippet_list(request):
    """
    list all code snippets, or create a new snippet
    """
    if request.method == 'GET':
        snippets = Snippet.objects.all()
        serializer = SnippetSerializer(snippets, many=True)
        return Response(serializer.data)

    elif request.method == 'POST':
        serializer = SnippetSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
  1. GET获取单个code snippetPUT更新单个code snippetDELETE删除单个code snippet
@api_view(['GET', 'PUT', 'DELETE'])
def snippet_detail(request, pk):
    """
    retrieve, update or delete code snippet
    """
    try:
        snippet = Snippet.objects.get(pk=pk)
    except Snippet.DoseNotExist:
        return Response(status=status.HTTP_404_NOT_FOUND)

    if request.method == 'GET':
        serializer = SnippetSerializer(snippet)
        return Response(serializer.data)

    elif request.method == 'PUT':
        serializer = SnippetSerializer(snippet, data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    elif request.method == 'DELETE':
        snippet.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

和上一步的views明显不同的是,我们不再需要关心输入(request)输出(response)的数据类型,REST框架已经帮我们处理好了

为URLs添加可选格式后缀

如上一步所说的,REST框架已经帮我们处理好了输入(request)输出(response)的数据类型,也就意味着一个API可以去处理不同的数据类型,在URLs中使用格式后缀可以帮助我们处理类似这样的url: https://192.168.0.103/snippets.json

  • 首先我们需要在views中添加形参format=None
def snippet_list(request, format=None):

def snippet_list(request, format=None):
  • 然后我们修改urls.py
from django.conf.urls import url
from rest_framework.urlpatterns import format_suffix_patterns
from snippets import views

urlpatterns = [
    url(r'^snippets/$', views.snippet_list),
    url(r'^snippets/(?P<pk>[0-9]+)$', views.snippet_detail),
]

urlpatterns = format_suffix_patterns(urlpatterns)

调用接口

  • 在启动服务器前,先修改settings.py中的ALLOWED_HOSTS,方便后面通过外部浏览器请求接口
ALLOWED_HOSTS = ['*']
  • 启动服务器(别管时间,每天晚上回来,让Win10从睡眠状态恢复,虚拟机的IP和时区总会变 🙁 ,懒得每次都改了)
(django_rest_framework) [root@localhost tutorial]# python manage.py runserver 0:80
Performing system checks...

System check identified no issues (0 silenced).
November 21, 2017 - 02:47:02
Django version 1.11.7, using settings 'tutorial.settings'
Starting development server at https://0:80/
Quit the server with CONTROL-C.
  • 打开另一个shell窗口,发送请求
(django_rest_framework) [root@localhost django_rest_framework]# http https://127.0.0.1:80/snippets/
HTTP/1.0 200 OK
Allow: POST, GET, OPTIONS
Content-Length: 505
Content-Type: application/json
Date: Mon, 20 Nov 2017 18:51:07 GMT
Server: WSGIServer/0.2 CPython/3.6.3
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

[
    {
        "code": "foo = \"bar\n\"",
        "id": 1,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    },
    {
        "code": "print \"hello, world\"\n",
        "id": 2,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    },
...
]
  • 我们可以添加HTTP HEADERS来控制返回数据的数据类型
  1. json
(django_rest_framework) [root@localhost django_rest_framework]# http https://127.0.0.1:80/snippets/ Accept:application/json
HTTP/1.0 200 OK
Allow: POST, GET, OPTIONS
Content-Length: 505
Content-Type: application/json
Date: Mon, 20 Nov 2017 18:52:27 GMT
Server: WSGIServer/0.2 CPython/3.6.3
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

[
    {
        "code": "foo = \"bar\n\"",
        "id": 1,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    },
    {
        "code": "print \"hello, world\"\n",
        "id": 2,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    },
]
  1. html
(django_rest_framework) [root@localhost django_rest_framework]# http https://127.0.0.1:80/snippets/ Accept:text/html
HTTP/1.0 200 OK
Allow: POST, GET, OPTIONS
Content-Length: 8139
Content-Type: text/html; charset=utf-8
Date: Mon, 20 Nov 2017 18:53:39 GMT
Server: WSGIServer/0.2 CPython/3.6.3
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

<!DOCTYPE html>
<html>
  <head>



        <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
        <meta name="robots" content="NONE,NOARCHIVE" />


      <title>Snippet List – Django REST framework</title>



          <link rel="stylesheet" type="text/css" href="/static/rest_framework/css/bootstrap.min.css"/>
...
  • 或者我们直接可以添加url后缀来控制返回数据的数据类型
  1. json
(django_rest_framework) [root@localhost django_rest_framework]# http https://127.0.0.1:80/snippets.json
HTTP/1.0 200 OK
Allow: POST, GET, OPTIONS
Content-Length: 505
Content-Type: application/json
Date: Mon, 20 Nov 2017 18:55:27 GMT
Server: WSGIServer/0.2 CPython/3.6.3
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

[
    {
        "code": "foo = \"bar\n\"",
        "id": 1,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    },
    {
        "code": "print \"hello, world\"\n",
        "id": 2,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    },
...
]
  1. html
(django_rest_framework) [root@localhost django_rest_framework]# http https://127.0.0.1:80/snippets.api
HTTP/1.0 200 OK
Allow: POST, GET, OPTIONS
Content-Length: 8160
Content-Type: text/html; charset=utf-8
Date: Mon, 20 Nov 2017 18:56:35 GMT
Server: WSGIServer/0.2 CPython/3.6.3
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

<!DOCTYPE html>
<html>
  <head>



        <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
        <meta name="robots" content="NONE,NOARCHIVE" />


      <title>Snippet List – Django REST framework</title>



          <link rel="stylesheet" type="text/css" href="/static/rest_framework/css/bootstrap.min.css"/>
          <link rel="stylesheet" type="text/css" href="/static/rest_framework/css/bootstrap-tweaks.css"/>
...
  • 类似的,我们可以发送不同类型的数据给API
  1. post form data
(django_rest_framework) [root@localhost django_rest_framework]# http --form POST https://127.0.0.1:80/snippets/ code="hello world post form data"
HTTP/1.0 201 Created
Allow: POST, GET, OPTIONS
Content-Length: 110
Content-Type: application/json
Date: Mon, 20 Nov 2017 18:58:58 GMT
Server: WSGIServer/0.2 CPython/3.6.3
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "code": "hello world post form data",
    "id": 6,
    "language": "python",
    "linenos": false,
    "style": "friendly",
    "title": ""
}
  1. post json data
(django_rest_framework) [root@localhost django_rest_framework]# http --json POST https://127.0.0.1:80/snippets/ code="hello world post json data"
HTTP/1.0 201 Created
Allow: POST, GET, OPTIONS
Content-Length: 110
Content-Type: application/json
Date: Mon, 20 Nov 2017 18:59:44 GMT
Server: WSGIServer/0.2 CPython/3.6.3
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "code": "hello world post json data",
    "id": 7,
    "language": "python",
    "linenos": false,
    "style": "friendly",
    "title": ""
}
  • 在请求时添加--debug后缀可以查看请求的详细信息
(django_rest_framework) [root@localhost django_rest_framework]# http --json POST https://127.0.0.1:80/snippets/ code="hello world post json data" --debug
HTTPie 0.9.9
Requests 2.18.4
Pygments 2.2.0
Python 3.6.3 (default, Nov  4 2017, 22:19:41) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-16)]
/root/.pyenv/versions/3.6.3/envs/django_rest_framework/bin/python
Linux 3.10.0-693.el7.x86_64

<Environment {
    "colors": 8,
    "config": {
        "__meta__": {
            "about": "HTTPie configuration file",
            "help": "https://httpie.org/docs#config",
            "httpie": "0.9.9"
        },
        "default_options": "[]"
    },
    "config_dir": "/root/.httpie",
    "is_windows": false,
    "stderr": "<_io.TextIOWrapper name='<stderr>' mode='w' encoding='UTF-8'>",
    "stderr_isatty": true,
    "stdin": "<_io.TextIOWrapper name='<stdin>' mode='r' encoding='UTF-8'>",
    "stdin_encoding": "UTF-8",
    "stdin_isatty": true,
    "stdout": "<_io.TextIOWrapper name='<stdout>' mode='w' encoding='UTF-8'>",
    "stdout_encoding": "UTF-8",
    "stdout_isatty": true
}>

>>> requests.request(**{
    "allow_redirects": false,
    "auth": "None",
    "cert": "None",
    "data": "{\"code\": \"hello world post json data\"}",
    "files": {},
    "headers": {
        "Accept": "application/json, */*",
        "Content-Type": "application/json",
        "User-Agent": "HTTPie/0.9.9"
    },
    "method": "post",
    "params": {},
    "proxies": {},
    "stream": true,
    "timeout": 30,
    "url": "https://127.0.0.1:80/snippets/",
    "verify": true
})

HTTP/1.0 201 Created
Allow: POST, GET, OPTIONS
Content-Length: 110
Content-Type: application/json
Date: Mon, 20 Nov 2017 19:00:45 GMT
Server: WSGIServer/0.2 CPython/3.6.3
Vary: Accept, Cookie
X-Frame-Options: SAMEORIGIN

{
    "code": "hello world post json data",
    "id": 9,
    "language": "python",
    "linenos": false,
    "style": "friendly",
    "title": ""
}
  • 在浏览器中发送请求
  1. 在浏览器中发送请求,默认会返回html类型的数据

  2. 可以像之前那样,加上url后缀,来请求json数据

关于

本人是初学Django REST framework,Django REST framework 学习纪要系列文章是我从官网文档学习后的初步消化成果,如有错误,欢迎指正。

学习用代码Github仓库:shelmingsong/django_rest_framework

本文参考的官网文档:Tutorial 2: Requests and Responses

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